corrected errors in shear estimator module

msg/soaring_controller_wind.msg

@@ -5,3 +5,5 @@ uint64 timestamp			# time since system start (microseconds)
 float32[3] wind_estimate                            # WIND ESTIMATE IN ENU FRAME
 float32[3] wind_estimate_filtered                   # LP-FILTERED WIND ESTIMATE IN ENU FRAME, USED BY INDI CONTROLLER
 float32[3] position                                 # position of the current estimate in the soaring frame
+
+bool valid                                          # tell, if estimate is valid for shear estimator

msg/soaring_estimator_shear.msg

@@ -9,5 +9,12 @@ float32 by                  # wind offset in y-direction
 float32 h                   # vertical position of shear layer in soaring frame
 float32 a                   # shear strength
 
+float32 sigma_vx            # covariance of vx
+float32 sigma_vy            # covariance of vy
+float32 sigma_bx            # covariance of bx
+float32 sigma_by            # covariance of by
+float32 sigma_h             # covariance of h
+float32 sigma_a             # covariance of a
+
 bool params_healthy         # plausibility check
 uint64 reset_counter        # filter reset counter